(1) Field of the Invention
This invention pertains to the reforming of hydrocarbons in the presence of a catalyst composite. This invention also pertains to a new catalyst composition containing a platinum group component and a method for making the catalyst. Pertinent U.S. patent classification for the subject matter of this invention is Class 208, Subclasses 64, 65, 133 and 143, and Class 252, Subclases 461 and 466 PT--reforming of hydrocarbons with noble metal-containing catalysts.
The catalyst of this invention comprises a platinum group component and a phosphorous component with a porous support material. The catalyst is made by compositing a platinum group component with a porous support material and then contacting that composite with phosphorus or a compound of phosphorus. The catalyst is particularly useful in the catalytic reforming of hydrocarbons boiling in the gasoline range to produce a high octane reformate suitable for gasoline blending or a high aromatics content reformate suitable as a petrochemical feedstock.
(2) Description of the Prior Art
U.S. Pat. No. 2,349,827 discloses using the phosphates of metals like aluminum and magnesium, for example, as catalysts for reforming hydrocarbons. This patent, however, does not disclose utilizing platinum as a catalytic metal as is required in our invention.
U.S. Pat. No. 2,441,297 discloses adding an aluminum salt of a pentavalent phosphorous compound to a catalyst support material for improved heat stability and catalyst life in a wide variety of reactions, including reforming of hydrocarbons. The preferred phosphorous compound is aluminum orthophosphate which is precipitated with the preferred alumina support. This patent, however, does not disclose compositing a platinum group component with a porous support material and then contacting that composite with phosphorus or a compound of phosphorus as is required in our invention.
U.S. Pat. No. 2,890,167 discloses a reforming catalyst comprising a metal or mixtures of metals from Group VIII of the periodic table, a compound of phosphorus and a cracking component. The cracking component is the support material which may be at least two refractory inorganic oxides together or a refractory inorganic oxide and halogen. This patent discloses broadly that the phosphorous compound may be added with the other catalytic components in any manner, but it specifically recites only two methods, namely; impregnating the support material with a solution of a phosphorous compound, and compositing the phosphorous compound with the cracking component support material by cogelation or coprecipitation, for example, when the cracking component is being prepared. This patent does not disclose compositing a platinum group component with a porous support material and then contacting that composite with phosphorus or a compound of phosphorus as is required in our invention.
U.S. Pat. No. 3,224,831 discloses broadly treating a porous support material and platinum composite with a compound of phosphorus selected from the group consisting of the acids of phosphorus and ammonium phosphate. Catalysts prepared by the method disclosed in this patent are useful in the catalytic oxidation of hydrocarbon and carbon monoxide constituents which are present in the exhaust gas of internal combustion engines. In this method, however, the sequence in treating the catalyst composite with the phosphorous compound is not critical as it is in our invention: according to this patent the support material can be first treated with the phosphorous compound and then that composite impregnated with the platinum solution; or, the support material can be impregnated with a common solution of the phosphorous compound and the platinum compound; or, the support material can be first impregnated with the platinum solution and then that composite treated with the phosphorous compound. Also in the method of this patent the phosphorus-treated support material and platinum composite is subjected to an air oxidation at temperatures from 300.degree. to 1000.degree. C. before being subjected to a hydrogen reduction step. In our invention, on the other hand, the phosphorus-treated support material and platinum group component composite is not subjected to an intermediate oxidation step before being reduced.
U.S. Pat. No. 3,227,658 discloses contacting a catalyst containing a Group VIII metal and alumina at elevated temperatures with an activating agent selected from the group consisting of the volatile chlorides and bromides of boron and phosphorus and the mixed chlorobromides thereof. The catalysts disclosed in this patent are useful in the isomerization of hydrocarbons. This treatment with the gaseous boron or phosphorous halides adds halide to the catalyst for increased isomerization activity. The activating treatment comprises contacting the catalyst with the gaseous activating agent at temperatures in the range of 700.degree. to 1500.degree. F., preferably 1000.degree. to 1300.degree. F., for a period of at least 0.1 hour and up to 10 hours or more. After this treatment additional activity may be obtained or these catalysts by subliming a small amount of aluminum chloride or aluminum bromide onto the catalyst to add even more halide. In our invention, on the other hand, it is not necessary to contact the support material and platinum group component composite with chlorides or bromides of phosphorus, nor is it necessary to treat the catalyst with the phosphorous component at such high temperatures.
U.S. Pat. No. 3,642,658 discloses contacting a Group VIII metal surface, especially nickel or platinum, with a Group V compound of the general formula X.sub.3 M, where X is an organic radical, a hydrogen or a halogen atom and M is an atom on phosphorus, arsenic or antimony so that the atomic ratio of the Group V component to the Group VIII component is from 0.01 to 0.5. The catalysts disclosed in this patent are useful in the hydrogenation of diolefins to mono-olefins. In the catalyst of our invention, on the other hand, the phosphorus to platinum group component atomic ratio is greater than 0.5; preferably this ratio is from about 0.5 to about 20.0.
U.S. Pat. No. 3,706,815 discloses depositing the chelates of a Group VIII noble metal and a polyphosphoric acid on a porous support material. The catalysts disclosed in this patent are useful in the isomerizing of hydrocarbons. This patent does not disclose compositing a platinum group component with a porous support material and then contacting that composite with phosphorus or a compound of phosphorus as is required in our invention.